Abstract
Background
Cold-water immersion is the gold standard for field treatment of an exertional heat
stroke (EHS) casualty. Practical limitations may preclude this method and ice sheets
(bed linens soaked in ice water) have emerged as a viable alternative. Laboratory
studies suggest that this is an inferior method; however, the magnitude of hyperthermia
is limited and may underestimate the cooling rate in EHS casualties.
Objective
Our aim was to determine the prehospital core cooling rate, need for continued cooling
on arrival to the emergency department, and mortality rate associated with ice sheet
use.
Methods
De-identified retrospective data were obtained from emergency medical services (EMS)
and included presence or absence of altered mental status, cooling measures applied
prior to EMS arrival, and time and core temperature (Tc; rectal) on-scene and on hospital arrival. Cooling rate was calculated from time
and temperature data. Mortality data were obtained from the US Army Combat Readiness
Center.
Results
There were 462 casualties that met inclusion criteria. The cooling rate for the entire
sample was 0.07°C ± 0.08°C · min−1. EHS casualties with an observed initial Tc < 39°C had an en route cooling rate of 0.03°C ± 0.04°C · min−1 vs. initial Tc ≥ 39°C cooling rate of 0.16°C ± 0.08°C · min−1. There was one fatality due to EHS, for a mortality rate of 0.20% (95% CI 0.01–1.20%).
Conclusions
The cooling rate in EHS casualties with initial Tc ≥ 39°C was approximately double that reported in laboratory studies. The observed
mortality rate was comparable with casualties treated with cold-water immersion. Our
data suggest that ice sheets provide a viable alternative when practical constraints
preclude cold-water immersion.
Keywords
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Article info
Publication history
Published online: December 19, 2022
Accepted:
December 13,
2022
Received in revised form:
November 7,
2022
Received:
June 2,
2022
Publication stage
In Press Uncorrected ProofFootnotes
Data included in this article were presented at the annual meeting of the American College of Sports Medicine, June 1–4, 2022.
RECEIVED: 2 June 2022; FINAL SUBMISSION RECEIVED: 7 November 2022; ACCEPTED: 13 December 2022
Identification
Copyright
Published by Elsevier Inc.
